Checking growth rate

Here is the theoretical growth rate (labelled mma) compared to AstroBEAR's (labelled visit) over 1 e-folding time-

They are within ~0.1% of each other by the end of the sim. Is this close enough, i.e. what we should expect??

Here is the same set up, over 5 e-folding times:

By the end of 5 e-folding times, however, they are within 5% of each other.

How does this data seem as a test for self-gravity in the code?

The initial perturbation is small, with amplitude 0.001*rho0.

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Comments

1. Jonathan -- 11 years ago

While the total density is only off by 5%, it is the perturbation that matters - and that looks like it is off by a factor of 2 or so. And I think I expect AstroBEAR to grow faster than linear after a few e-folding times… not slower. Can you outline how you calculated the analytic growth rate in computational units?